1. Field of Inventions
The present inventions relate generally to devices for performing therapeutic operations on body tissue.
2. Description of the Related Art
There are many instances where electrosurgical devices are used to form therapeutic lesions in tissue. Therapeutic lesions are frequently formed to treat conditions in the heart, prostate, liver, brain, gall bladder, uterus, breasts, lungs and other solid organs. Electromagnetic radio frequency (“RF”) may, for example, be used to heat and eventually kill (i.e. “ablate”) tissue to form a lesion. During the ablation of soft tissue (i.e. tissue other than blood, bone and connective tissue), tissue coagulation occurs and it is the coagulation that kills the tissue. Thus, references to the ablation of soft tissue are necessarily references to soft tissue coagulation. “Tissue coagulation” is the process of cross-linking proteins in tissue to cause the tissue to jell. In soft tissue, it is the fluid within the tissue cell membranes that jells to kill the cells, thereby killing the tissue.
The tissue coagulation energy is typically supplied by an electrosurgical unit (“ESU”) during the therapeutic procedure. More specifically, after a catheter, surgical probe or clamp has been connected to the ESU, and the electrodes or other energy transmission elements on the catheter, surgical probe or clamp have been positioned adjacent to the target tissue, energy from the ESU is transmitted through the energy transmission elements to the tissue to from a lesion. The amount of power required to coagulate tissue ranges from 5 to 150 W.
Some electrosurgical procedures require the use of more than one electrosurgical device. One example of such a procedure involves the formation of therapeutic lesions to treat cardiac conditions such as atrial fibrillation. Here, a clamp may be used to create a first transmural epicardial lesion around the right pulmonary vein pair and a second transmural epicardial lesion around the left pulmonary vein pair. Thereafter, if needed, a surgical probe may be used to create a linear transmural epicardial lesion between the right and left pulmonary vein pairs. A linear transmural lesion that extends from the lesion between the right and left pulmonary vein pairs to the left atrial appendage may also be created.
The present inventors have determined that conventional lesion formation devices are susceptible to improvement. For example, the present inventors have determined that there may be more efficient and cost effective ways, in terms of materials, manufacturing, sterilization, shipping, etc., to provide physicians with the capabilities of two separate devices, such as the aforementioned separate clamp and surgical probe.